ATTENUATION OF ULTRASOUND IN SKELETAL-MUSCLE

Ultrasonic attenuation in fresh and 5% formalin fixed beef skeletal muscle was measured, as a continuous function of frequency, in the range 1-8 MHz, for muscle fiber orientations both parallel and normal to the direction of propagation. Good agreement was found in all cases between 2 independent sets of measurements employing transmission and reflection techniques, respectively. A power law dependence of attenuation coefficient on frequency shows an exponent that is not significantly different from unity. For propagation normal to the fibers attenuation values are found as 1.1 .+-. 0.15 and 1.6 .+-. 0.15 dB cm-1 MHz-1 for fresh and fixed tissue, respectively, the corresponding values for parallel propagation being 2.9 .+-. 0.23 and 4.1 .+-. 0.25 dB cm-1 MHz-1.